Fiducial and schematic update


#1

Let’s say I add a few fiducial in PcbNew. Now, if I run an update from schematic these are typically removed :face_with_raised_eyebrow:
So I thought I can lock them, but the lock option isn’t available for these footprints…
I can add them to schematics, OK… almost: now they appear in BOM :face_with_raised_eyebrow:
How are they thought to be used with KiCad?

Edit: Moreover, they report DRC overlap error, if “overlapping” a component :face_with_raised_eyebrow:


#2

I don’t know what footprints you are using as fiducials: I have always locked the fiducial footprints successfully, as any other footprint.

Of course they will raise a DRC error if overlapping a footprint or a track. Fiducials are “copper dots” and electrons don’t differienciate copper by its intended function.

Furthermore, if a fiducial is overlapped by a footprint, it will be hidden by the component soldered to that footprint making the fiducial useless.


#3

If you add a fiducial in schematic, then import it to PcbNew, it can be locked. If you load a fiducial footprint in PcbNew (without being in the schematic first) it can’t.

A fiducial is used by pick and place machine before you place any component on board.
The DRC error is shown when the component courtyard overlaps the fiducial one, which is way larger than the central pad. IMHO this is questionable.


#4

I have been using KiCad since 2005 and never had this problem. What footprint are you using for fiducials?

Many machines also use the fiducials while placing components. Maybe I’m wrong.

Sure. It can be questionable. The DRC for courtyard has been recently implemented in KiCad. If the overlappin is only about the courtyard and not about electrical contact, you can ignore it.


#5

Smallest fiducial as supplied with standard KiCad 5.1 install.
Funny enough, if I try it today it behaves also with fiducials added in PcbNew, while yesterday I could see the “Locking” context menu item only for other parts… mmh…

Anyway, this is an example. All the footprints are from standard supplied ones, two images are worth two million words and a few thousands pixels.